Just add transitions to sabotage an XWSS, then add/remove other transitions, to sabotage the sabotage of the XWSS:

Pulsar Life variant:

`x = 7, y = 5, rule = B3-nry4knt/S238`

2b2o$o4bo$2bo3bo$o5bo$b6o!

HighLife variants:

`x = 27, y = 7, rule = B3-e5i6i/S2-c3`

2b2o9b2o9b2o$2ob2o5b3ob2o4b4ob2o$4o6b5o5b6o$b2o8b3o7b4o$4o6b5o5b6o$2ob

2o5b3ob2o4b4ob2o$2b2o9b2o9b2o!

`x = 18, y = 13, rule = B3-y6/S23`

3b2o10bo$bo4bo6bo3bo$o11bo$o5bo5bo4bo$6o6b5o4$6o6b5o$o5bo5bo4bo$o11bo$

bo4bo6bo3bo$3b2o10bo!

LowDeath variants:

`x = 6, y = 7, rule = B3aijqr4knt5i6i/S2-c38`

b5o$o4bo$5bo$obobo$5bo$o4bo$b5o!

`x = 7, y = 13, rule = B3-nry4knt6/S238`

3b2o$bo4bo$o$o5bo$6o4$6o$o5bo$o$bo4bo$3b2o!

Which gives us a rule with 8 2c/4 spaceships:

`x = 27, y = 41, rule = B3-ey5i6i/S2-c3`

12bo9b2o$o2bo6bo3bo5bo4bo$4bo10bo10bo$o3bo5bo4bo4bo5bo$b4o6b5o5b6o6$

12bo9b2o$10bo3bo5bo4bo$15bo10bo$10bo4bo4bo5bo$11b5o5b6o4$11b5o5b6o$10b

o4bo4bo5bo$15bo10bo$10bo3bo5bo4bo$12bo9b2o8$12bo9b2o$o2bo6bo3bo5bo4bo$

4bo10bo10bo$o3bo5bo4bo4bo5bo$b4o6b5o5b6o2$b4o6b5o5b6o$o3bo5bo4bo4bo5bo

$4bo10bo10bo$o2bo6bo3bo5bo4bo$12bo9b2o!

DryLife XWSS variants:

`x = 5, y = 4, rule = B3-c4kr7c/S234i`

b4o$obobo$4bo$o2bo!

`x = 6, y = 5, rule = B34ak7c/S234i`

b5o$o2bobo$5bo$o3bo$2bo!

`x = 7, y = 5, rule = B34ak7c/S234i`

b6o$o3bobo$6bo$o4bo$2b2o!